Catalytic synthesis and decomposition of peroxycarboxylic acids - green catalytic synthesis of green compounds
Résumé
Peroxycarboxylic acids are widely used in industry for disinfection and bleaching as well as fine chem. The synthesis of peroxycarboxylic acid from carboxylic acid and hydrogen peroxide is a reversible reaction. Due to the slow kinetics of this reaction, acid catalysts are needed. This paper describes a kinetic study of carboxylic acids perhydrolysis in the presence of sulfuric acid at various molar reactant ratios, reaction temps. and catalyst concns. The influence of water and acidic catalysts were taken into account to develop a plausible kinetic model. A "greener" way of peroxycarboxylic acid synthesis using solid acid catalysts was investigated. Cation exchange resins showed a higher catalytic activity than aluminosilicates under comparable exptl. conditions. A general model was developed, comprising the kinetic and mass transfer effects in porous catalyst particles (i.e., Amberlite IR-120) in batch reactors. The concns. in the bulk phase and inside the catalyst particles were predicted by the model. The stability of peroxycarboxylic acid was investigated. Decompn. of peroxycarboxylic acid takes place in the liq. phase, but products of decompn., carbon dioxide and oxygen are transferred to gas phase. An anal. method was developed to det. the decompn. of the peroxycarboxylic acid in the liq. phase by means of chem. anal. of the gas phase. The method is based on online mass spectroscopy (MS). A math. model for the semi-batch gas-liq. system was developed.